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PENTAX DSLR LENS ON K3 ?


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#1 polychronou chris

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Posted 28 January 2008 - 06:43 AM

HI EVERYBODY.

I AM A NEWBIE AT THE FORUM.
I WAS THINKING OF USING LENSES FROM THE PENTAX DSLR RANGE WITH MY K3 CAMERA.
THESE LENSES ARE SHARP,THEY ARE AFFORDABLE COMPARED TO A PRIME CINE LENS AND THEY ARE DESIGNED FOR 3:2 RATIO LIKE THE STANDARD 16MM IMAGE RATIO.
THE FLANGE FOCAL DISTANCE OF PENTAX DSLR'S IS SIMILAR TO THAT OF A K3 IF I ' M NOT MISTAKEN.THE PROBLEM IS THE M42 MOUNT THAT HAS TO REPLACED.
HAS ANYONE TRIED SOMETHING LIKE THIS BEFORE ,IS IT POSSIBLE ? ARE THERE ANY ADAPTERS FOR PENTAX KAF2 MOUNT LENSES ?
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#2 Saul Rodgar

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Posted 28 January 2008 - 11:26 AM

HI EVERYBODY.

I AM A NEWBIE AT THE FORUM.
I WAS THINKING OF USING LENSES FROM THE PENTAX DSLR RANGE WITH MY K3 CAMERA.
THESE LENSES ARE SHARP,THEY ARE AFFORDABLE COMPARED TO A PRIME CINE LENS AND THEY ARE DESIGNED FOR 3:2 RATIO LIKE THE STANDARD 16MM IMAGE RATIO.
THE FLANGE FOCAL DISTANCE OF PENTAX DSLR'S IS SIMILAR TO THAT OF A K3 IF I ' M NOT MISTAKEN.THE PROBLEM IS THE M42 MOUNT THAT HAS TO REPLACED.
HAS ANYONE TRIED SOMETHING LIKE THIS BEFORE ,IS IT POSSIBLE ? ARE THERE ANY ADAPTERS FOR PENTAX KAF2 MOUNT LENSES ?


This subject has been discussed before. You can use older, cheaper and good quality Pentax m42 mount lenses directly on the K3 without having to change the mount or use adaptors. It works really well, but you will double your focal lenght no matter what 35mm lens you use on 16mm, so you know. DSLR lenses I have not heard anyone working with, it could work if they are all manual, no internal camera-computer controlled aperture and/ or focus only, and they have a compatible mount.
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#3 Will Montgomery

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Posted 28 January 2008 - 01:03 PM

The lenses would theoretically cover the 16mm frame but you need to be able to manually adjust the aperture; something that may not be possible with all modern DSLR lenses (Nikon's newest don't provide a manual aperture ring).

It really would be easier just to pick up some older m42 Super-Takumar Pentax lenses. They are pretty reasonable.

There are certainly adapters from m42 to Nikon and Canon mounts, not sure about the one you mentioned.
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#4 Leo Anthony Vale

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Posted 28 January 2008 - 04:13 PM

THE FLANGE FOCAL DISTANCE OF PENTAX DSLR'S IS SIMILAR TO THAT OF A K3 IF I ' M NOT MISTAKEN.THE PROBLEM IS THE M42 MOUNT THAT HAS TO REPLACED.
HAS ANYONE TRIED SOMETHING LIKE THIS BEFORE ,IS IT POSSIBLE ? ARE THERE ANY ADAPTERS FOR PENTAX KAF2 MOUNT LENSES ?


M42 lenses can be adapted to K mount cameras. The K mount was Pentax's bayonet replacement for the
screww mount.
Since the K mount is wider, it can't be adapted for an M42 camera.

& Saulie, the focal length remains the same, the viewing angle is what changes.
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#5 Saul Rodgar

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Posted 28 January 2008 - 05:40 PM

Saulie, the focal length remains the same, the viewing angle is what changes.


Right, what I meant is that a 50mm focal lenght 35mm photo lens used in 16mm photography renders an image equivalent (give or take) to a 100mm lens in 35mm photography. Its field of view halves since only the center portion is used at half the length and width of 35mm photography. But I refered to it as doubling the focal lenght instead of narrowing the field of view in half, which is the correct term. Oftentimes in this situation the two terms are used indistinctly, innacurately perhaps, for the sake of simplicity. Technically you are correct.
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